JPH0525287A - Airtight mixture - Google Patents

Abstract

PURPOSE:To provide an airtight mixture which is useful as an airtight sealant for filling voids in an electric wire or cable and as a watertight sealant for filling voids or openings in other structural materials. CONSTITUTION:100 pts.wt. base resin consisting of an ethylene-alpha-olefin copolymer or an ethylene-alpha-olefin-diene terpolymer is mixed with up to 50 pts.wt. inorg. filler and then with 0.1-0.5 pt.wt. org. peroxide, and semicrosslinked to give the objective airtight, which is rich in stickiness (adhesiveness), highly heat-resistant, free of sagging due to melting even at a high temp., and excellent in airtightness (watertightness) and in moldability such as extrudability or formability into tape.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention is useful as an airtight seal material filled in voids such as electric wires and cables, or as a watertight seal material filled in voids and gaps of other structural materials. Airtight mixture.

[0002]

2. Description of the Related Art Heretofore, various airtight materials (including watertight materials) have been proposed, for example, in the case of electric wires and cables, such as a type of covering by extrusion and a type of sandwiching a tape-shaped material. There is. As a mixture used as such an airtight material, in many cases,
A polymer having polarities such as ethylene-vinyl acetate copolymer and chlorinated polyethylene having improved adhesiveness is used as a base resin. In addition, some have proposed that a filler is added to a liquid polymer so as to exhibit watertightness due to its adhesiveness.

[0003]

However, in the case of the above-mentioned conventional airtight material, (1) the watertightness is low and the airtightness is insufficient, and (2) the heat resistance of the mixture. There were shortcomings, such as being poor.

The present invention has been made on the basis of such conventional drawbacks.

[0005]

Means for Solving the Problem and Its Action According to the present invention, after adding an inorganic filler in an amount of 50 parts by weight or less to 100 parts by weight of a base resin, 0.1 to 0.5 parts by weight of an organic peracid is added. Is added to carry out semi-crosslinking to impart adhesiveness to the airtight mixture.

The base resin used in the present invention is
For example, ethylene-α-olefin copolymer and ethylene-
Examples of the α-olefin-gen copolymer include the base resin, which has higher heat resistance than EVA and chlorinated polyethylene, which are used as the base resin of conventional water-tight materials.

An inorganic filler such as calcium carbonate, clay, talc, silica or carbon may be added to the base resin. This inorganic filler may be added without any addition, but when it is added, properties such as processability and mechanical properties are improved. However, considering these characteristics, it is preferable to limit the amount to 50 parts by weight with respect to 100 parts by weight of the base resin. This is because if the amount exceeds 50 parts by weight, problems such as a decrease in the filling rate into the void portion and a decrease in airtightness will occur.

As a cross-linking agent for cross-linking the base resin, ketone peroxides such as methyl ethyl ketone peroxide and acetylacetone peroxide,
Peroxyketals such as 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane and n-butyl-4,4-bis (t-butylperoxy) valerate, t-butylhydroper Hydroperoxides such as oxide, cumene hydroperoxide, p-menthane hydroperoxide, di-t-
Butyl peroxide, dicumyl peroxide (DC
P), dialkyl peroxides such as 2,5-dimethyl-2,5-di (t-butylperoxy) hexane,
Diacyl peroxides such as lauroyl peroxide and benzoyl peroxide, peroxydicarbonates such as di-iso-propyl peroxydicarbonate, dimyristyl peroxydicarbonate and bis (4-t-butylcyclohexyl) peroxydicarbonate And organic peracids such as peroxyesters such as t-butylperoxypivalate, t-butylperoxy-2-ethylhexanoate, t-butylperoxybenzoate, etc. It is 1 to 0.5 parts by weight. This addition amount is such that the base resin is semi-crosslinked. Here, the term "half-crosslinked" refers to a state in which only about half of the degree of crosslinking (gel fraction = about 80% or more) that is usually obtained in the base resin is crosslinked.

In obtaining such semi-crosslinking, the amount of addition is 0.1 to 0.5 parts by weight because the amount of the organic peracid is too small when the amount is less than 0.1 parts by weight, and the desired semi-crosslinking is obtained. If the amount exceeds 0.5 part by weight, the amount of the organic peracid is too large, and crosslinking exceeding half-crosslinking can be achieved.

When the semi-crosslinked mixture of the present invention is used, for example, in an electric wire or a cable, even if the mixture is used at a high temperature, the semi-crosslinked effect causes
Melt dripping or deformation of the mixture is prevented. Also,
Since the crosslinking is suppressed to be low in this way, for example, the adhesiveness (adhesiveness) with the conductor is good, and the excellent airtight performance (the same watertight performance) is exhibited.

In the present invention, other fillers can be added if necessary. For example, a crosslinking aid can be used in combination with the crosslinking agent of an organic peracid. Above all,
When a metal-containing monomer (zinc methacrylate, calcium methacrylate, barium methacrylate, etc.) is added, the adhesiveness with the conductor metal can be improved and more excellent airtightness can be obtained. Further, a coupling agent for surface treatment can be added.

[0012]

[Examples] When manufacturing a cable in which an EP rubber insulator is coated on a 7-strand conductor, each airtight mixture shown in Table 1 is attached to the center wire of the conductor and the outer periphery of the 7-strand conductor (Examples). 1 to 4 and Comparative Examples 1 to 3) were extruded and covered, and then EP rubber insulator was extruded and covered, and then subjected to batch CV cross-linking to obtain each cable. The gas leak property and the drip property of each of these cables were examined.

Gas leak resistance was measured by making a 1-foot sample of each cable and adding 0.5% to one end of this sample.
The pressure was applied at a pressure of Kg / cm ² for 1 hour, and the presence or absence of gas leak from the other end was examined. Further, the drip property was examined by placing the sample of each cable in a high temperature of 200 ° C. for 1 hour, and checking the presence or absence of drip of each hermetic mixture at that time.

[0014]

[Table 1]

From this table, it can be seen that each of the cables according to the present invention (Examples 1 to 4) has excellent gas leak property and good airtightness (watertightness), and at the same time, has excellent drip property. It can be seen that it has excellent heat resistance. On the other hand, in the case of each of the cables (Comparative Examples 1 to 3) lacking the conditions of the present invention, it is understood that the gas drip property is good, the drip property is bad, or both are bad.

Although the airtight mixture of the present invention is used as a constituent material (airtight sealing material) of electric wires or cables in the above-mentioned embodiments, the present invention is not limited to this application and other Of course, it can be used for various purposes.

[0017]

As is apparent from the above description, the airtight mixture according to the present invention has 100 parts by weight of a base resin such as an ethylene-α-olefin copolymer or an ethylene-α-olefin-gen copolymer. After adding 0 to 50 parts by weight of an inorganic filler, 0.1 to 0.5 parts by weight of an organic peracid to add semi-crosslinking to give adhesiveness, so that it has excellent heat resistance. And, since it is semi-crosslinked, it does not melt even under high temperature, and it is excellent in airtightness (watertightness) because it is rich in adhesiveness (adhesiveness), and there is no excessive addition of an inorganic filler. An airtight mixture that is excellent in processability such as extrusion and tape form can be obtained.

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Claims (2)

[Claims] 1. An organic peracid of 0.1 to 0.5 is added after adding 50 parts by weight or less of an inorganic filler to 100 parts by weight of a base resin.
An airtight mixture characterized by being provided with adhesiveness by adding a part by weight and semi-crosslinking. 2. The hermetic mixture according to claim 1, wherein the base resin is an ethylene-α-olefin copolymer or an ethylene-α-olefin-gen copolymer.